Is anybody running a set of 285/70/17 tires on there stock auto 6.7 ctd?The reasion i ask this is i have a low milage set of BFG A/T TKO tires left over from my gmc and was wondering if you lost or gained milage with them? I have the stock 265 on my truck now and would like to use the 285 tires. But not if they are going to cost me fuel milage. Does anybody have any picks of theses on there truck.thanks Mopar72

 

I run toyo in that size but I had them put on within 200 miles of buying the truck. My spedo is right at 1 MPH off at 65 so I can't see there beeing any real difference in the MPG. BTW, the truck looks so much better with 285's than with the 265's

Chris

 

I don't think your truck will ever notice 285's on it. They are about an inch difference in height. I would run them, there free and a great tire. Scotty

 

I put 2857017 Bridgestone Dueler AT revos on right after I drove off the lot, have amost 6k on truck and average aroud 18mpg non-towing, truck looks so much better amost wish I went to a 305, the 265 just looked way too small for my taste. Go with them!!!

 

I have them too and my mileage did not change any. They looked so much bigger in comparison the the stock 265s but now that they are on the truck I wish I had gotten bigger. Oh well, another two years and I will probably need new ones anyways....

I did not get my pinion factor reset for the larger tires. I figure a 3% increase in the footprint of the tire and that gives me the true mileage when I am figuring mpgs. Also at 60 mph on the speedo you will actually be doing around 62mph....

 

I ditched the OEM Michelin LTX A/S's around 2100 miles and installed some LT285/70R17 Firestone Destination A/T's. I had the dealer re-program the tire size....my truck turns around 1350 rpm @ 55 mph now; as best I remember, it saves about 100 rpm at this speed.

Greg

 

I havnt seen much if any miliage difference with 285's. Maybee a little but not enough to grip about. Plus, the ride withe 285 is like night and day. out of the 3 sets I bought for my last truck the best were the mickey thompson atz baja's. Best wear, best ride, great off road and in snow , reasonably priced, and dont feel spongy like the bfg's when you get a load on them. The worst were the nittos. They looked good though.

 

Thanks guys i found out my mom has a router. So looks like i will be putting my hummer h2 wheels on. If i get them on i will try and post a pick of my truck.Thanks Bobby

 

I put 305-65-17 BFG MT KM II's on mine and can not tell any diff in MPG. It looks SOOOOOO much better than stock.

 

I have 35x12.5x17's on mine and could really tell a difference. This is a dually though so theres 6 of em! I went from getting 14.5 to 15 to now getting a consistent 12.5 unloaded. I unplugged my EGR today though so we will see what happens. I never expected great mileage when I went with the tires. I am fixing to get som 24" Alcoas with 37's. I know my mileage will go down. But thats a sacrifice I am willing to take for the looks. I plan on getting a CAI and Edge Juice w/ Attitude also so maybe that will make up for some of it.

 

I also wanted to add that this is the third CTD I have had (2 5.9's and 1 6.7) I have never seen more that 16 MPG out of any of them. I drive really good too never more than 70 MPH. Im used to it but never really knew how everyone else gets so much better mileage.

 

A lot of it is just probably driving style. Just giving it too much pedal each time you take off from a stop will kill your mileage. Try resetting your overhead next time you are at a red light. When it turns green give it a bunch of pedal to get moving. Watch how low the number drops. Factor this in for everytime you stop and start and it really adds up.......

My 98 got OK mileage, the 03 got great mileage, my 07 didn't, my 08 got bad mileage until deleting parts now it's better than my 03 except for the towing mileage which still sucks...

 

My 05 got ok mileage, my 06 got a little worse, my 07 went down the drain but am working on that and its getting better.

 

My 06 gets great mileage (consistently over 20) with the 285/75R17's. I think alot of it is driving style like the rest have said. Plus, the more aggressive tread designs eat a little more fuel. Even with the G56 having a higher OD ratio, they still seem to get better mileage than :most" any of the automatics. It seems either that manual drivers are easier on the go pedal or there is less drivetrain parasitic loss. Scotty